sam: disallow destructive commands in groups and looping constructs

This should fix segfaults for commands like `:{ q i/foo/ }` or
`:x/pattern/ q` where a command invalidates the current window.

The checks are a bit too strict, for example a destructive command at the
end of a non-nested group would be fine, but is currently also rejected.

1 files changed, 2 insertions, 0 deletions

diff --git a/sam.h b/sam.h
index 0ea9c2f..e94b175 100644
--- a/sam.h
+++ b/sam.h
@@ -18,6 +18,8 @@ enum SamError {
 	SAM_ERR_MARK,
 	SAM_ERR_CONFLICT,
 	SAM_ERR_WRITE_CONFLICT,
+	SAM_ERR_LOOP_INVALID_CMD,
+	SAM_ERR_GROUP_INVALID_CMD,
 };
 
 bool sam_init(Vis*);